Inhaled Cannabis Reduces Diabetic Neuropathic Pain

Recent study has shown that inhaled cannabis has a dose-dependent reduction in pain intensity…

Almost half of diabetes patients experienced diabetic peripheral neuropathy through their lifetime. Previous animal studies suggest that cannabis may be effective in reducing neuropathic pain, but there were no studies to focus especially on patients with refractory or painful diabetic peripheral neuropathy.
Researchers from the University of California conducted a randomized, double-blinded placebo-controlled study in 16 patients with painful diabetic peripheral neuropathy. Their aim was to evaluate the efficacy and tolerability of inhaled cannabis for treating pain caused by diabetic peripheral neuropathy. Inhaled cannabis was preferred over smoking because inhalation was shown to reach peak effects faster; and it is easier to titrate.

Each patient in the study was randomized to take placebo or low (1% tetrahydrocannabinol [THC]), medium (4% THC), or high (7% THC) doses of cannabis. Baseline spontaneous pain, evoked pain, and cognitive testing were performed. After patients received their randomly assigned doses, pain scores were measured again at 5, 15, 30, 45, and 60 minutes and then every 30 minutes for an additional 3 hours. Cognitive testing was performed at 5 and 30 minutes and then every 30 minutes for an additional 3 hours. A total of 4 single-dose sessions were performed during the length of the experiment.

According on the results of the study, there was a significant difference in spontaneous pain scores between doses (P < .001). Specific significant comparisons were placebo versus low, medium, and high doses (P = .031, .04, and <.001, respectively) and high versus low and medium doses (both P < .001). High dose cannabis was associated with significant effect on both the foam brush and Von Frey evoked pain score (both P < .001). Despite positive results, there was a significant euphoria and somnolence in all patients.

The results of this small, short-term study provide the evidence that cannabis may reduce diabetic neuropathy pain in a dose-dependent manner. According to Mark S. Wallace, M.D., a professor of anesthesiology, University of California San Diego School of Medicine, “[analgesic effects of cannabis may] benefit in neuropathic pain syndromes, including treatment-refractory diabetic peripheral neuropathy.” However, the impaired cognitive effects of cannabis may limit its acceptability as an analgesic.

Practice Pearls:

Inhaled cannabis would yield a dose-dependent reduction in spontaneous and evoked pain.